title: Unfolding X-ray spectra using a flat panel detector.
abstract: It is difficult to measure the energy spectrum of X-ray tubes due to the pile up effect produced by the high fluence of photons. Using attenuating materials, appropriate detector devices and the Monte Carlo method, primary X-ray spectrum of these devices can be estimated. In this work, a flat panel detector with a PMMA wedge has been used to obtain a dose curve corresponding to certain working conditions of a radiodiagnostic X-ray tube. The relation between the dose curve recorded by the flat panel and the primary X-ray spectrum is defined by a response function. Normally this function can be approximated by a matrix, which can be obtained by means of the Monte Carlo method. Knowing the measured dose curve and the response matrix, the primary X-ray spectrum can be unfolded. However, there are some problems that strongly affect the applicability of this method: i.e. technical features of the flat panel and inherent characteristics of the involved radiation physics (ill-posed problem). Both aspects are analyzed in this work, concluding that the proposed method can be applied with an acceptable accuracy for spectra without characteristic lines, for instance, tungsten anode in the 50-70 kVp range.
authors.forename: Sergio
authors.initials: S
authors.lastname: Gallardo
authors.forename: Belén
authors.initials: B
authors.lastname: Juste
authors.forename: Fausto
authors.initials: F
authors.lastname: Pozuelo
authors.forename: José
authors.initials: J
authors.lastname: Ródenas
authors.forename: Andrea
authors.initials: A
authors.lastname: Querol
authors.forename: Gumersindo
authors.initials: G
authors.lastname: Verdú
mesh_terms: D003198:Computer Simulation; D006801:Humans; D009010:Monte Carlo Method; D011856:Radiographic Image Enhancement / Q000295:instrumentation*